Annuals can be fertilized in midsummer with a low-analysis fertilizer to keep them lush and healthy. Bulbs should be fertilized immediately after flowering with a high-phosphorus fertilizer such as bone meal. Nonbulbous perennials grow best if fertilized in the early spring. Summer or fall fertilization of perennials can harm the plants by keeping them too succulent as winter approaches.
Many summer annuals must be continuously tended to remove dead flower blossoms, a practice termed dead-heading. Plants such as petunias and geraniums are especially demanding. Combining deadheading with IPM scouting can reduce labor costs, but requires floral crew workers to be knowledgeable of integrated pest management if it is to be cost effective.
Annuals are most likely to benefit from pinching back, but certain perennials such as hardy mums will also do better if pinched. Pinching removes the terminal shoot on each branch of the flower and allows the lateral shoots to develop, thereby creating a fuller plant. Soft pinching is done with the thumb and forefinger and removes the terminal bud or, at the most, the terminal bud and first set of laterals. Hard pinching may shorten each stem by one third or more. Most flowers benefit by a hard pinch soon after being set out, followed by one or two soft pinches during the summer. With perennials such as mums, whose flower bud initiation is tied to a photoperiod response, the last pinch should not be after mid-July if a good flower display is to be seen in the autumn.
Flowers such as petunias or rose moss that are valued for their profuse blossoms, can be kept from getting leggy and going to seed by severely cutting them back about midsummer. A tool as indelicate as a pair of grass clippers can be used to provide a hard pinch if the planting is extensive. A period of several weeks with few flowers will follow until new reproductive growth begins. However, the fresh look and new flowers that result will carry the annuals right into the fall season.